An Elderly Person
Use a tog rating appropriate to the season and the warmth of the bedroom. An all-seasons duvet would be a good investment. Use the 4.5 tog during warm summer months and the 9.0 tog duvet for spring and autumn. During winter, you can make a cosy 13.5 tog duvet by pairing up the 9.0 and 4.5 tog duvets. As older people can suffer from uncomfortable temperature fluctuations, they may prefer using a 4.5 or 9.0 tog duvet year-round, layering-up with extra blankets or bedspreads if they start to feel the cold, and removing layers if they start to feel too warm.
And remember to think about the duvet fill. Natural fill duvets, such as silk, wool and cotton, help regulate temperature for a much more comfortable night's sleep. An elderly person with restricted movement may also prefer a lighter duvet that they can lift with ease, in which case consider a light but warm down-rich duvet.